Printing apparatus are common in the art. Printing apparatus generally comprises a plurality of printing rollers, at least one ink fountain, and at least one inking blade that is positioned adjacent to one of the inking rollers. The inking blade is a generally longitudinally extending member the longitudinal length of which being generally parallel with the axis of the inking roller. One edge of the inking blade is positioned adjacent to, but not continguous with, the inking roller such that a gap is formed between the inking blade edge and the inking roller. The distance of the gap is varied by adjusting the position of the inking blade in relation to the inking roller. The distance between the inking blade and the inking roller is proportional to the amount of ink that may be adhered to the inking roller, which in turn determines the intensity of the ink that is printed on a medium, generally paper.
Since the intensity of the ink may not be uniform across a single piece of print, the distance of the gap between the inking blade and the inking roller needs to, necessarily, be different at different locations along the entire length of the inking roller. The adjustment of the gap at each discrete location is generally performed by manually-operated adjusting devices which are mounted on the inking blade. Each of these adjusting devices varies the intensity of the ink on a segment of the resultant print, generally referred to as a zone. The adjusting devices in the prior art are generally referred to as keys. Examples of such prior art printing apparatus and ink adjusting devices are illustrated in Crum, U.S. Pat. No. 3,747,524; Murray et al., U.S. Pat. No. 3,958,509; Crum et al., U.S. Pat. No. 4,008,664; and Schramm, U.S. Pat. No. 4,328,748.